Robert Charlton summarizes an article by Glenn Gabe linked in the above thread, "He suggests that one possibility is that the Phantom tremors might be adjustments of thresholds for each quality factor. I myself having been looking forward to some kind of relaxation on similar product pages of the sort needed in certain types of B2B ecommerce websites. It would be great to have the quality of the rest of the site cushion the algo into going softer on similar products of the kind that manufacturers need to list." It's definitely worth a read.

Glenn Gabe wrote:

...I saw the latest Phantom tremor starting on 7/14/15. I’ve seen the impact with companies I am helping now, but I’ve also had new companies reach out to me explaining what they are seeing. And when tremors roll out, Phantom victims can see more impact (mostly negative based on my analysis, but there has been some positive movement).

The July 2015 SERP changes thread is also rumbling with people saying that they're seeing crazy stuff like 20% ranking increases, potentially sustainable traffic bumpts, etc.

User Atomic and others point to a piece in SE Roundtable which speculates a new phantom update to the algorithm. Many people in the comments say that "it's very minor."